Universe v Ironing

I have found something useful to do with my retirement! I have time to think about things. I am thinking about the Universe, which is much more satisfying than thinking about the ironing.

OK, this is where I am so far. Cosmologists: please feel free to correct me.

The Universe  is expanding. What this means is, that on a large scale, superclusters of galaxies are moving away from each other. However, the reason they are moving away from each other is not that they are moving through space, but that the space between superclusters is expanding, and taking the superclusters along with them.

The Universe is probably infinite, and always has been, even when it was a tiny dot. The key to getting your head round this is to refrain from asking the perfectly reasonable, though flawed question, well hold on a minute, if the Universe was once a tiny dot, then what did it expand into? The answer is to remember that the Universe has not expanded into anything, (ie into space), as space is an actual property of the Universe, and has always included all the space there is.

So as space expands, the matter in space is just taken along for the ride. The Universe is not expanding into space. All the space there is, is itself expanding. Also, everything is expanding away from everything else: there is no centre to the Universe, and there never was.

Even if the Universe turns out to be finite, there is no edge. Contrary to Douglas Adams, there is no End of The Universe, and certainly no Restaurant there. All that would happen if you travelled far enough across the Universe, is that you would end up back at Earth.

A great analogy which helps me, is to imagine that the Universe is the surface of a balloon. All the superclusters are marked by dots on the balloon. Now blow up the balloon more and what happens? The dots all get further apart. They have not moved across the surface of the balloon, but the balloon itself has expanded, forcing the dots apart and taking them along for the ride. Also, this analogy explains why there is no centre to the Universe: there is no centre to the dots on the balloon.

All fantastically difficult stuff to get your brain round. Still easier than pairing socks though.

Here's Eric Idle to explain everything.

"Makes you feel so small"

"Yeah. Can we 'ave your liver then?"

"Welll..allright."